Jan. 07, 2011

Pop Quiz: What do dynamite, dinosaurs, and dentifrice have in common? Answer: Diatomaceous earth, that's what!

Diatomaceous earth consists of the fossilized remains of diatoms, which are microscopic single-celled algae that use silica to form their bodies. Diatoms originated around the Early Jurassic period and continue to flourish today. There are thousands of shapes, forms, and species of diatom and they are found in every single part of the world -- from the bottom of the ocean to mountain lakes, from North Pole to South Pole.

Beckett at Calvert Cliffs

Maryland has a large untapped fossil deposit known as Calvert Cliffs. Beckett and I visited the state park there looking for ancient shark teeth which can usually be found after storms at low tide. We happened to be there on a day that had an unusually high tide -- so high that we couldn't even go on the beach. The water was all the way up to the cliffs! So we made do with exploring the rocks and stones around the high side of the cliffs and we found many great shell fossils that date back to the Miocene era.

We are always careful when going out on an expedition -- we stay in the designated areas and only take specimens, fossils, and minerals where permitted. We wear safety glasses when we break up rocks looking for fossils and we always pack out our trash and make sure we leave the area cleaner than we found it. We're planning to go back to Calvert Cliffs as soon as we can, on a day we can get on the beach, so we can find some ancient shark teeth.

Beckett's rock sample composed of diatoms and ancient shells

Diatomaceous earth, a light sedimentary rock that can be crushed into a fine powder, was discovered in Germany in the 1830s and was found to have many unique properties. One early use was pioneered by Alfred Nobel who used it to stabilize nitroglycerin so it could be transported safely. He called the mixture dynamite and it was the source of his vast wealth -- the same wealth he used to found and fund the prize we know today as the Nobel Peace Prize.

Diatomaceous earth is also used as a filter -- most often for swimming pools, but over the years it has filtered every type of liquid including the oil in cars. It can also be used as insecticide, as a base for hydroponic gardening, as an absorbent for toxic and non-toxic spills, and as an anti-worm agent. Diatomaceous earth is mined and sold in many forms: food grade, medical grade, industrial grade -- it really has many many amazing uses. Now, most toothpaste is made from hydrated silica that is formed in a factory and not mined, but many toothpastes still use diatomaceous earth.

_____Science Dad, AKA Vince Harriman, is a freelance writer living in Annapolis. His two sons, Beckett-6 and Rowan-2 1/2 ask him ‘why’ approximately 6,549 times a day.